1. Field of the Invention
The present invention relates to an optical synchronizer which synchronizes the timing of signal light with a plurality of wavelengths, the timing of which is not synchronized (asynchronous) in terms of time.
2. Description of the Related Art
Optical signal processing technologies have been studied to break through the present performance limit of optical technology. Optical signal processing technologies such as signal light regeneration, an optical switch, and wavelength conversion are expected to be realized. In order to realize said technologies, an all-optical signal processing technology which executes entire processing at a level of light using an ultra-wide band and ultrahigh-speed characteristics of light is promising, and a great deal is expected of this technology as that which realizes a transparent action without depending on the bit rate, pulse shape, etc. of a signal. In such an all-optical type of signal processing, generally, nonlinear optical effects are used, and since many of nonlinear optical effects have an ultrahigh-speed processing performance, the all-optical signal processing can be expected to produce a far superior performance than a conventional opto-electric conversion type of signal processing. Other functions which can be expected to be realized by the all-optical signal processing technology, but cannot be realized by the opto-electric conversion type signal processing are the functions which process multiple wavelengths simultaneously. One method which realizes the function which processes multiple wavelengths is to convert an asynchronous signal whose wavelength has been multiplexed into a synchronizing signal of one wavelength. If this function is realized, the ultrahigh-speed characteristics of all-optical signal processing can be put to practical use, and a compact signal processing device can be realized.
Described in Patent Document 1 is the method of forming the waveform of signal light, and the technology which enables waveform shaping of signal light as it is without depending on a modulation rate and format is disclosed therein. Described in Patent Document 2 is the method of performing waveform shaping of signal light, and the technology which realizes 3R functions of signal light as it is disclosed therein. In Patent Document 3, the technology for performing waveform shaping of signal light is also disclosed.
Patent Document 1: Kokai (Jpn. unexamined patent publication) 2003-15097
Patent Document 1: Kokai (Jpn. unexamined patent publication) 2003-107541
Patent Document 1: Kokai (Jpn. unexamined patent publication) 2003-209516
There is an optical 3R signal regeneration technology as one of the main optical signal processing technologies. In this case, generally, signal light which should be 3R-regenerated and a recovered optical clock pulse are inputted to an optical switch as an optical AND circuit, and data which the signal light has is transferred to the regenerated optical clock pulse by the AND operation. The optical 3R regeneration of 160 Gb/s has already been experimented and verified using an optical switch using nonlinear optical effects in an optical fiber. For example, the response time of nonlinear optical effects in an optical fiber is as fast as a femtosecond order, so that nonlinear optical effects have a possibility of realizing optical 3R regeneration of a Tb/s order. The biggest problem is how compactly signal processing can be realized for a wavelength division multiplex signal.